An overtone is a sinusoidal component of a waveform, of greater frequency than its fundamental frequency. Usually the first overtone is the second harmonic, the second overtone is the third harmonic, etc.

Usage of term

Use of the term overtone is generally confined to acoustic waves, especially in applications related to music. Despite confused usage, an overtone is either a harmonic or a partial. A harmonic is an integer multiple of the fundamental frequency. A partial or inharmonic overtone is a non-integer multiple of a fundamental frequency.

An example of harmonic overtones:

Not all overtones are necessarily harmonics, or exact multiples of the fundamental frequency. Some musical instruments produce overtones that are sharper or flatter than harmonics. The sharpness or flatness of their overtones is one of the elements that contributes to their sound; this also has the effect of making their waveforms not perfectly periodic.

Since the harmonic series is an arithmetic sequence (1f, 2f, 3f, 4f...), and the octave, or octave series, is a geometric sequence (f, 2×f, 2×2×f, 2×2×2×f, ...), this causes the overtone series to divide the octave into increasingly smaller parts as it ascends.

The overtones of a sound determine its sound quality or timbre and its frequency spectra.

Contrast with fundamental.

In barbershop music, the word overtone is often used in a different (though related) way. It refers to a psychoacoustic effect in which a listener hears an audible pitch that is higher than, and different from, the four pitches being sung by the quartet. This is not a standard dictionary usage of the word "overtone." The barbershopper's "overtone" is created by the interactions of the overtones in each singer's note (and by sum and difference frequencies created by nonlinear interactions within the ear).

Overtone singing, also called harmonic singing occurs when the singer amplifies voluntarily one overtone in the sequence available given the fundamental tone he/she is singing. Overtone singing is a traditional form of singing in many parts of the himalayas, tibetans, mongols and tuvans are known for their overtone singing.

See also

• Harmonic series (music)
• Just intonation
• Xenharmonic
• Stretched octave

Source: originally from Federal Standard 1037C, but edited.

Tuning

Alikvotní tón | Obertöne | Boventoon | צליל עילי